Engine starter



J. E. BUXTON ENGINE STARTER June 24, 1947.

2 Sheets-Sheet 1 Filed Aug. 2, 1945 w as 32 7 g gINfiVENTOR. I %5% WITNESS A ORNEY Patented June 24, 1947 ENGINE STARTER James E. Buxton, Elmira, N. Y., assignor to Bendix Aviation Corporation, Elmira Heights, N. Y., a corporation of Delaware Application August 2, 1945, Serial No. 608,515

8 Claims.

The present invention relates to an engine starting mechanism and more particularly to that type of starting mechanism in which .the engine starter remains operatively connected to the engine until the engine is reliably self-operative.

It is an object of the present invention to pro vide an engine starting mechanism having novel 'means for maintaining the engine driving memher in engagement with an engine member during the starting operation.

It is another object to provide such a device having a latch for maintaining the engine driving member in engagement with the engine member during the starting operation.

It is another object to provide such a device embodying a limiting or confining ring to prevent the latch from releasing in response to centrifugal force while the starting switch is closed.

It is another object to provide such a device in which the confining ring is operated. in conjunction with the starting switch to hold the latch member in operative position until a true start of the engine is secured.

It is a further object to provide such a device in which the confining ring is a component part of the drive and is light in weight while being easy to assemble.

It is a further object to provide'such a device in which the confining ring is concentrically and slidably mounted on an axially concentric cylindrical member of an engine starter so as to obtain reduction of vibration by dynamic balance and good alignment between .the axis of the ring and the axis of rotation of the latch.

Further objects and advantages will be apparent from the following description and accompanying drawing, in which: a

Fig. 1 is a side elevation partly in section of an engine starting drive embodying a preferred form of the invention, showing the latch and confining ring therefor in idle position, the electrical starting system being .shown diagrammatically;

Fig. 2 is a view similar to Fig. 1 showing the starting drive and associated parts in cranking or operative position; i

Fig. 3 is a view similar to Fig. 1 showing the starting drive in overrunning position with the latch moved outwardly into contact with the confining ring; r

Fig. 4 is a cross-sectional view of the drive on the line 4-4 of Fig. 1 showing the latch in idle position;

Fig. 5 is a cross-sectional view taken on the line 55 of Fig. 3 showing the latch in operative position; and

Fig. 6 is a perspective view of a fragment of a' screw shaft illustrating the latching abutment and clearance space for the latch.

In Fig. 1 of the drawing, there is illustrated a shaft I which may be the extended armature shaft of an electric starting motor, not shown, supported at its inner end by a bearing 2 on the starting motor and at its outer end by a bearing 3 within an extended housing 4 attached to the starting motor. Adjacent the starting motor, a drive head 5 is fixedly mounted on shaft l' by any suitable means such as an anchor pin 6. A cupshaped housing member I having a double-D opening 8 therein is closely fitted to a corresponding double-D section 9 on the head 5 and bears against a shoulder H on the drive head which is so located that a radial flange ll of the housing I is positioned over the pin 6 so as to lock the pin in assembled position. A lock wire I3 is seated in a groove [4 on head 5 in position to bear against the flange l2 and hold the housing 7 assembled on the head. An operating member in the form of a screw shaft [5 provided with threads [6 and a flange I1 is journalled on the motor shaft I, and a disc [8 is fixed as by welding or brazing at H] on the end of the screw shaft against the flange IT.

Yielding driving means are provided between the disc [8 and housing 1 in the form of a block 2l' of elastic material such as rubber loosely fitting the interior of the housing and adapted to be compressed between the fiange l2 and said disc.

An engine driving member in the form of a pinion 22 is slidably journalled on the shaft I for meshing engagement with an engine member such as a fiy-wheel ring gear 23 of the engine to be started. Axial and rotational movements are imparted to the pinion by a control member in the form of a nut 24 threaded on the screw shaft 15 and fixed as indicated at 25 in the end of a barrel 2% by any suitable means such' as brazing.

A separable driving connection is provided between the barrel 26 and pinion 22 in the form of a dental clutch 21 which is made operative by the final axial movement of the nut 24 after the meshing movement of the pinion has been arrested. The driving plate 28 of the clutch 21 is joined to the barrel 26 by lugs 29 on the plate fitting within slots 3| in the barrel and. held therein by a lip 32 on the barrel spun over a ring 33. A driven clutch plate 34 is fixed to the pinion 22 by suitable means such as brazing as shown at 35, and is'provide d' with dentals 36 mating with dentals 31 on plate 28. Clutch plates 28 and 34 are normally held out of engagement by the compression spring 38, the separation of the plates being limited by a thimble 39 having a flange 40 at one end forming a stop for the driven clutch member 34, and retained in the end of the barrel 26 by means of a peripheral flange interposed 'between driving clutch plate 28 and-ring 33.

According to the present invention, means under the control of the operator are provided for maintaining the pinion 22 in operative engagement with the engine gear 23 until the'erlgine is reliably self-operative. As bestishowniin Fig-'4,

this means is in the form of a latch i'l'pivote'd at 42 on the control nut and urged into engagement with the screw shaft by atorsion spring 43 so as to automatically latch 'the control nut 24 to the screw shaft [5 as the point 44-of the latch drops behind arr abutment surface 45 on the-screw shaft. :This abutment-45 is so located on the threads H; as to enable the latch to engage it when the yieldingdriving=member 21 is in relaxed-condition and theclutchdentals 36, 3'! are separated. For"thi s=purpose, one of the threads "46-on the screw'shaft l5- is cutaway to 'form a recess-at 46,-as=best shwn -in=Fig. 6, which permits the point'of the -latch to bear'on the root diameter of the 'thread'during the final move- ;ment of the control nut =whichcloses theclutch ;2-1.

Manuallycontrolled means are provided for holding the-latch inoperati-Veposition in the-form of-a confining ring 41 constructed as an'exten- -sion-of a sleeve member 48 which is slidably mounted on the cylindrical housing -'I. When ring *4"! is in the .plane of rotation of' thelatch duringthe startingoperation, the latch is not per- :mitted to-fiy outward under the influence of centrifugal forcecaused bythe-rotation of the barrel l'fiand accordingly maintainsJpinion 22 in mesh with the engine .gear 23 regardless of the speed of rotation-ofthe -parts.

Unitary means in the-:form of apush-rod 49 ';under .the control o fthe operator are provided for mov-ing the sleeve 48 into operative position and concurrently closinga starting switch I. 'A shift fork-52 n 'i'ixedly mounted on the vpush rod .fl by meanspf-a set screw 5 0 and projects downwardly through an opening 53in the housing extension 4. The arms 54 o f-the forksupportrollers 'SS within' an-'annularchanne1-56 in a shift cllar' 5T which is mounted on the sleeve 48. Lugs 38 and a -snaplock ring 59 are :provided at the sides o'f-the collar?! tolongitudinally confine it onsaid sleeve. "Push-rod 49 is'journalled 'in'; brackets 6! and Y'G'Z a'nd a bridging member -64 of the" starting switch'il is slidably mounted on said rod and normally held against a stop shoulder '53 thereor i' by means of aspring 6E seated on theshi f t "fork-'52. Electrical energy is supplied to the startingmotor 'S'Mby a battery 66 which is 'groiindedat fil and connected by a lead 68'to contact 'l-l'il of the" starting switch, the opposite contact 'IL I thereof be ingconnected -by a lead 12 to the motorSM which is .g-roundedat T3 tocom- .plete the starting circuit.

iiIhQlongitudiiial travelof the push-rod 49 is preferably limite'd'by astop collar 14 (Fig. 2) lfixed t hereon' in vpositionq to abut against the bfaclnt 6i when the rodis so positioned as to place the confining ring 4'! in the plane of the latch"4 lv when the parts :are :in cranking position.

op'eration,- the operator either directly or-inidiretly' 'mo'ves 'the :pushro d 49 to-the right in and-moves' the' shoulder'fiii'away from the bridging switch member 64 untilthe motion'is arrested by the stop collar [4. Immediately after the latch 21 is fully traversed to operative position, the

--ring extension 4'! follows and covers it, thereby confining it against outward movement from "latchedrposition as long as the operator holds the vipush-rod inshifte'd position. When the engine fires, the" acceleration of the pinion 22 by the engine gear 23 is transmitted through the clutch Zltdthecontrol nut 24 whereby the nut moves -ion to overrun I freely.

rback on the screw shaft t6 permitting the clutch to be opened by spring 38 so as to allow the pin- The backward movement =of the nut is-limitecLhowever, by the engagement -of latch with'the abutment45, which engage- -ment'is positively maintained by the confining ring tl-so 'as-to'holdthe pinion in mesh with the engine gear.

-If'theengine-does'not continueto be self --operative, the operatormaintains the rod 49'instarting position with the -ring'4'l in therpath of rotation of the latch 4| and crankingof the engine will be resumed assoon as the engine slows down to a speed-correspondingto that-of the starting motor. When-reliable operationof the engine is secured, the operator retracts thepush-rod'49 to first per- -mit the latch 4i tomove out by centrifugal force and release the pinion, and then to open the switch iii to thereby deenergize the starting motor.

Although but one embodiment of the invention has been shown and described in-detail, it will be understood thatchanges maybemade in the form and'arrangementof the parts without departing from the spiritof the inventionas-defined in the claims appended hereto.

What is claimed is 1. -In an engine starting -mechanism,"a motor 'shaft an-operating member mounted thereon to rotate therewith, an engine driving-member slidably journalled on said shaft :for movement into and-out of engagement with a member of an engine-to be started, means including a control member and a clutch'between said operating and engine driving members for transmitting axial and rotational "movement from the operating member to said engine driving member, releasable means on said-control member for maintaining said-engine driving member operatively connected with said engine member and means 'under the control-of the operator for confining said releasable means.

2. In-an engine'starter, amotor shaft, a screw shaft mountedthereon to rotate therewith, a pinion slidably journalled on said motor shaft for movement into and out of engagement with a member of 'an'engine-to be started, means including a-control nut and a clutch between said screw shaft and pinion for transmitting axial and rotational movement from thesc'rew :shaft to said'pinion, means including a latch on said control-nut for holding the pinion in mesh'with said engin gear, and manually controlled means forholding the latch in operative position regardless-ofthe rotational speed of the pinion.

3. In an engine starter, a motor shaft, a screw shaft mounted thereon to rotate therewith, a

pinion slidably journalled on said motor shaft for movement into and out of engagement with a member of an engine to be started, a control nut threaded on said screw shaft and means including a clutch between said nut and pinion for transmitting axial and rotational movement from the screw shaft to said pinion, a centrifugal latch pivoted on the control nut, means normally pressing the latch against said screw shaft, said screw shaft having an abutment surface cooperating with said latch to hold the pinion in meshed position, and a ring member movable by the operator into the plar of rotation of said latch to prevent delatching thereof.

4. In an ngine starting mechanism, a starting circuit including a motor and a starting switch, a motor shaft, a screw shaft mounted on the motor shaft and driven therefrom, a pinion slidably journalled on said motor shaft for meshing with and rotating an engine gear, means for actuating the :pinion including a nut member on said screw shaft, and a clutch connection between said control nut and pinion made effective by the final forward movement of said control nut; a latch member and a spring member for normally holding the latch member in contact with said screw shaft, both members being mounted on said control nut and cooperating with an abutment on the screw shaft to keep the pinion meshed with the engine gear, said latch being released by centrifugal force; and a ring for preventing unlatching of said latch, and unitary actuating means for moving said ring out of the path of rotation of said latch and simul-- taneously releasing said switch.

5. In an engine starting mechanism, a starting circuit including a motor and a starting switch, a motor shaft, a screw shaft mounted thereon and driven therefrom, a pinion slidably journalled on said motor shaft for meshing with and rotating an engine gear; means including a nut member on said screw shaft for actuating said pinion; a torsional connection between said control nut and pinion made effective by the final forward movement of said control nut, means for automatically latching said pinion in mesh with said engine gear, said means being responsive to centrifugal force for unlatchin said pinion, an annular member for preventing unlatching of said pinion, and manually controlled means for actuating said annular member in timed relation to the operation of said starting switch to release said latching means before the starting switch is opened.

6. In an engine starting mechanism, a. motor shaft, a housing member fixed thereon, a screw shaft journalled on said motor shaft and having a yielding driving connection to said housing, a pinion slidably journalled on said motor shaft for meshing with and rotating an engine gear, a control nut threaded to said screw shaft and a torsional connection including an enclosure member and a clutch between said nut and pinion, a

latch pivoted on said control nut and an abutment on said screw shaft for said latch to maintain said pinion in meshed position, and a sleeve under the control of the operator journalled on said housing and having an extension forming a confining ring for controlling said latch.

7. In an engine starting mechanism, a starting circuit including a motor and a starting switcln a motor shaft, a housing member fixed thereon, a screw shaft journalled on said motor shaft and having a, yielding driving connection to said housing, a pinion slidably journalled on said motor shaft for movement into and out of mesh with an engine gear, a control nut mounted on said screw shaft and means including a barrel member and a clutch fixed to said barrel member for actuating said pinion from the screw shaft, a torsion spring and a latch inwardly biased thereby, both spring and latch being mounted on said control nut for keeping said pinion in mesh with the engine gear, an axially movable sleeve having an integral ring portion journalled on said housing for locking said latch in operative position during the starting operation, and unitary means for moving said sleeve and starting switch in unison.

8. In an engine starting mechanism, a starting circuit including a motor and a starting switch, a motor shaft, a housing member fixed thereon, a screw shaft journalled on said motor shaft and having a yielding driving connection to said housing, said screw shaft being provided with a cut-away portion on one of its threads terminating at one end in an abrupt shoulder, a pinion slidably journalled on said motor shaft for movement into and out of mesh with an engine ear, a control nut on said screw shaft for actuating said pinion from the screw shaft, a centrifugally responsive latch and a spring for urging said latch toward the center of rotation of said screw shaft, both spring and latch being mounted on said control nut for retaining said pinion in mesh with the engine gear during cranking of the engine and preventing drifting of said pinion from idle position when said starting mechanism is inoperative, a thread of said screw shaft having a recess forming a radial abutment surface for contacting said latch in latch position, an axially movable sleeve journalled on said housing for preventing radial unlatching movement of said latch during the starting operation and manually controlled unitary means for moving said sleeve and switch in timed sequence.

JAMES E. BUXTON.

REFERENCES CITED UNITED STATES PATENTS Name Date Kearney Jan. 18, 1944 Number 

